Cavity wall and damp

[geraldthehamster]

My father has moved into a 1930s bungalow with cavity walls. Indoors, there is considerable damp low down on some walls. Outside, a concrete path goes round the house and is quite high. The strip alongside the wall is filled with gravel, but the gravel mostly bridges the damp course.

I understand the principle of how this can give the impression of "rising damp", when in fact the damp is penetrating above the damp course. However, how does damp penetrating the outer leaf give rise to corresponding damp on the inner leaf, and in the rooms? Does this indicate that the cavity itself is bridged low down?

What solutions might be appropriate?

 

[Alastairreid]

Suspended or concrete floors?
Cavities can be accessed by knocking out air bricks or brick in suspect areas.
Could be a number of things which you are already aware of, including leaking pipes.choked drains etc.

 

[^woody^]

That's the thing with cavity walls - they do not need a DPC on the external leaf, and even if there is a DPC, it matters not if the ground level is near or above it.

If damp is getting across a cavity wall at ground level then the problem is a bridged cavity. Nothing else.

 

[geraldthehamster]

Suspended or concrete floors?

Suspended